Film image display system

ABSTRACT

A developed film is illuminated to project its image onto a rear projection screen. A transparent case with a clear liquid filled therein is arranged, and the film is accommodated in the case. A writable transparent or translucent sheet is arranged over a front side of the rear projection screen.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 09/342,063,filed Jun. 29, 1999, U.S. Pat. No. 6,128,553.

BACKGROUND OF THE INVENTION

a) Field of the Invention

This invention relates to a film image display system, and specificallyto a medical film image display system useful for the explanation or thelike of a treatment to a patient.

b) Description of the Related Art

In a certain dental treatment, a dentist may conduct x-ray photographyof one or more teeth and the associated gum of a patient and may thenproceed with the treatment on the basis of the developed x-ray film. Inthis case, the treatment, orthodontics or the like is effected based onan informed consent, that is, after showing the developed film to thepatient and explaining the conditions of the tooth or teeth and atreatment plan to be followed.

Subsequent to x-ray photography, a film is successively developed, fixedand rinsed in a developing processor. Because this film cannot be viewedor checked as long as it is wet, it has been the conventional practiceto dry the developed film and then to view or check it by exposing thesame on the rear side thereof to light from a plane light source or thelike. A variety of methods are known for drying such a film, includingblowing warm air against the film. Whichever method is employed, sometime is needed to dry it.

Since it takes certain time to dry the film as mentioned above, theexplanation to the patient has to be deferred until the film dries. Ithas hence been impossible to promptly give an explanation to a patient.

Further, upon making an explanation to a patient about the conditions ofteeth and the details of a treatment, it should be easier for thepatient to understand the explanation if the dentist can write hisexplanation on the film. Conventional methods, however, do not permitwriting on films, so that such explanations are not fully understandablewith ease.

SUMMARY OF THE INVENTION

With the foregoing in view, an object of the present invention is toachieve a further improvement in the convenience of conducting atreatment by making use of an x-ray film and also of explaining thetreatment to the patient.

In one aspect of the present invention, there is thus provided a filmimage display system for displaying an image of a developed film byilluminating the developed film and projecting the image onto a rearprojection screen, wherein the system is provided with a transparentcase in which a clear liquid is to be filled, and the film isaccommodated in the case.

In another aspect of the present invention, there is also provided afilm image display system for displaying an image of a developed film byilluminating the developed film and projecting the image onto a rearprojection screen, wherein a writable transparent or translucent sheetis arranged over a front side of the rear projection screen.

Means for displaying the image of the film is not limited to theabove-described screen, but display means such as LCD (liquid crystaldisplay), CRT (cathode ray tube) or a plasma display can also be used.In the latter case, video signals are sent to such display means byusing image pickup means (such as CCD sensor, camera or the like) thatreads the image of the developed film.

According to the present invention, a wet film can be projectedimmediately. Further, writing is feasible over a projected image. Theconvenience of conducting a treatment by making use of an x-ray film andalso of explaining the treatment to the patient can therefore beimproved further.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a film image displaysystem according to a first embodiment of the present invention;

FIG. 2A is a front view of a film holder, FIG. 2B is a cross-sectionalview of the film holder, and FIG. 2C is a perspective view of atransparent case;

FIG. 3 is a front view of the film image display system;

FIG. 4 is a perspective view of a sheet cassette;

FIGS. 5A through 5C illustrate a modification of the film holder, inwhich FIG. 5A is a front view of a film, FIG. 5B is a front view of themodified film holder, and FIG. 5C is a cross-sectional view of themodified film holder taken in the direction of arrows VC—VC of FIG. 5B;

FIG. 6A is a cross-sectional view showing a film image display systemaccording to a second embodiment of the present invention, and FIG. 6Bis a perspective view of the film image display system according to thesecond embodiment of the present invention;

FIG. 7 is an enlarged cross-sectional view of a transparent case mountin the film image display system according to the second embodiment ofthe present invention;

FIG. 8 is an enlarged perspective view of a transparent case in the filmimage display system according to the second embodiment of the presentinvention; and

FIG. 9 is an exploded perspective view of a modification of the filmimage display system according to the second embodiment of the presentinvention, which shows another example of a writable sheet.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

Referring first to FIG. 1, the first embodiment of the present inventionwill be described. The film image display system, which is designated atnumeral 2, is a projector-type system and is provided with a housing 4and a base 6 which supports the housing 4 thereon. Inside the housing 4,there are arranged at an end thereof (at a right end as viewed inFIG. 1) a light source (lamp) 10 provided with a reflector 8 and at anopposite end thereof (at a left end as viewed in FIG. 1) a rearprojection screen 12. A Fresnel lens is mounted over a front side of thescreen 12. From the light source 10 toward the screen 12, a condenserlens (converging system) 14, a heat filter 16, another condenser lens(converging system) 18, a developed film 20 and a projection lens 22 arearranged successively.

The film 20 may be, for example, a dental x-ray film of 30×40 mm(already developed) and, as is depicted in FIGS. 2A and 2B, is mountedon a film holder 24. Through the film holder 24, an opening 24 a isformed. Stepped portions 24 b are formed around the opening 24 a, andthe film 24 is detachably fitted on the stepped portions 24 b. A fingergrip 24 c is formed extending from an upper part of the film holder 24.

The film holder 24 is accommodated in a transparent case 26 such as thatas shown in FIG. 2C. This transparent case 26 is provided with twocompartments 26 a, 26 b. The compartment 26 a is filled with water 28,while the compartment 26 b is empty. Handles 26 c are attached toopposite side walls of the transparent case 26, respectively. Anymaterial can be used as the material of the transparent case 26 insofaras it permits transmission of light from the light source 10. A coloredmaterial may be used.

On an optical path in the housing 4, a case receiver 30 such as thatdepicted in FIG. 1 is arranged, and the transparent case 26 is slidably(in the direction indicated by an arrow D in FIG. 2) placed in the casereceiver 30. The film 20 is placed in the water compartment 26 a when itis wet, but is placed in the empty compartment 26 b when it is dry. Byholding the handles 26 c, the transparent case 26 is caused to slide toplace the film 20 on the optical path. Accordingly, the film 20 isarranged so that it is illuminated by light from the light source 10.

The projection lens 22 is composed of one or more optical elements andprojects the image of the film on an enlarged scale onto the rear sideof the screen 12.

Over the front side of the screen 12, a sheet 32 is arranged asillustrated in FIG. 3. This sheet 32 is transparent, or is translucentto such an extent that an image T projected onto the screen 12 isvisible through the sheet 32. No particular limitation is imposed on thematerial of the sheet 32, and any material can be used insofar as itpermits writing with a writing instrument. The sheet 32 is applied withcross-ruled scale marks 32 a. These scale marks are shown as coarse onesin FIG. 3 to facilitate the description. Actually, however, finer scalemarks are used to permit a measurement on the basis of the imageprojected onto the screen 12 (for example, a measurement of the rootcanal length of a tooth). The scale of these scale marks is set inproportion with the magnification of the image such that actual lengthscan be measured by relying upon the scale marks 32 a.

The sheet 32 is supplied in the form of a cassette as depicted in FIG.4. Described specifically, the sheet 32 is wound on a spool 34 and isaccommodated within a cylindrical sheet cassette 36. A rod 37 isattached to a leading end portion of the sheet 32. Both above and belowthe screen 32, cylindrical sheet holders 38, 40 are mounted on thehousing 4, and the sheet cassette 36 is loaded in the sheet holder 40.The sheet holder 40 is provided with bearings (not illustrated), onwhich the spool 34 is supported. By these bearings, the spool 34 isnormally biased in a direction in which the sheet 32 is wound into thesheet cassette 36. On the other hand, the sheet holder 38 is providedwith a take-up spool 42, so that the sheet 32 is wound out of the sheetholder 40, extends over the front side of the screen 32, and is thentaken up on the take-up spool 42. As the sheet 32 is normally biasedunder tension toward the sheet holder 40, the sheet 32 remains in closecontact with the front side of the screen 12. The take-up spool 42 isrotated manually or by motor drive (not illustrated), whereby the sheet32 is taken up over a predetermined length or a desired length eachtime.

The take-up spool 42 is provided with means for finely adjusting ataken-up length although it is not illustrated in any drawing. As anexample of such fine adjustment means, a rotatable knob may be arrangedto rotate the take-up spool 42 via a gear mechanism which is providedwith a stopper (pawl or the like) for the prevention of reverserotation. The sheet can be taken up over a desired length by manuallyrotating the rotatable know in a winding direction. As the sheet 32 ispulled toward the sheet holder 40, release of the stopper allows thesheet 32 to move in the wound-in direction. As is readily appreciatedfrom the foregoing, the position of a desired one of the scale marks 32can be brought into registration with a specific part of the image bymanipulating the rotatable knob and the stopper to move the sheet 32over a very small distance.

As is depicted in FIG. 1, a cooling fan 44 is arranged below the lightsource 10, and cooling air is fed to the light source 10 through airinlet holes 4 a formed through the hosing 4. Behind the reflector 8, adrying compartment is formed. The drying compartment 46 is incommunication with the interior of the housing 4 through air outletholes 4 b, so that air which has been heated up by the light source 10advances to the drying compartment 46 through the air outlet holes 4 band is then discharged to the outside. If a wet film 21 is placed in thedrying compartment 46, it is promptly dried by warm air which isindicated by arrow marks in FIG. 1.

Use of the above-described film image display system 1 makes it possibleto perform good projection even in the case of a wet film shortly afterits development, because the film is placed in the water compartment 26a and is then exposed to light. It the wet film were projected as is, inother words, before drying the same, droplets or the like which stillremain on the film would also be projected so that no good image wouldbe available. The placement of the film in the water compartment 26 ahas made it possible to eliminate such a problem. Further, a film isaccompanied with slight ruggedness on surfaces thereof. If the film wereilluminated as is, the illuminating light would be irregularlyreflected. Immersion of the film in a liquid as described above caneliminate such ruggedness, thereby making it possible to avoid irregularreflection and hence to obtain a clear image.

According to the system described above, writing is feasible on thesheet 32. Understanding of an explanation to a patient can befacilitated further if an explanatory sketch is drawn over an image ofteeth. A fresh part of the sheet is then caused to appear by taking upthe sketch-bearing part of the sheet. This allows to make an explanationabout another image with reference to another explanatory sketch drawn othe fresh part of the sheet.

Further, the sheet 32 is applied with the scale marks 32 a. One of thescale marks 32 a can therefore be brought into registration with areference point on an image of teeth by finely adjusting the position ofthe sheet with the fine adjustment means. This makes it possible tomeasure a target part (for example, the root canal length of one of theteeth). Incidentally, the scale marks may also be formed directly on asurface of the screen 12 or a surface of the transparent case 26 withoutbeing limited to the sheet.

After finishing the projection, the film is transferred together withthe film holder to the drying compartment 46, where the film can bedried. The film so dried can then be projected by inserting it into theempty compartment 26 b and sliding the transparent case 26.

In FIGS. 5A through 5C, the modification of the film holder is depicted.In this modification, the film 20 is developed in a state fitted in aring-shaped frame 48. An opening 50 a is formed through a film holder50, and stepped portions 50 b are formed around the opening 50 a. Theframe 48 is detachably fitted on the stepped portions 50 b. A fingergrip 50 c is formed extending from an upper part of the film holder 50.The opening 50 a is formed in the same size and shape as the film 20.Accordingly, the shape of each stepped portion 50 b is determined suchthat a corresponding space 48 a, which is surrounded by the frame 48 andthe film 20 (see FIG. 5A), is shielded from light by the stepped portion50 b. To use the film in an upright position, it is only necessary toform an opening 50 d such that like the film, its longer sides extend inthe vertical direction as indicated by phantoms in FIG. 5B.

FIG. 6 illustrates an example in which LCD is used as display means. Thefilm image display system, which is designated at numeral 60, iscomposed of a base 62, a main body 64, and LCD 66. Over a front side ofthe display 66, a sheet 32 is arranged in a similar manner as in thesystem of FIG. 1. On a side wall of the main body 64, a transparent casemount 68 is formed. On this transparent case mount 68, a transparentcase 26 which is similar to that shown in FIG. 2C is placed. In thetransparent case 26, a film holder 50 similar to that depicted in FIGS.5A to 5C is accommodated. As a display, another display means such asCRT or a plasma display may be used besides LCD.

The film image display system 60 is provided with an external inputterminal 67 and a selector switch 69, both of which are for use with acamera for photographing the inside of the mouth (intraoral camera 80).The intraoral camera 80 is provided with a stick-shaped,intraorally-inserted section 82, a handle 84 and a cord 86. Theintraorally-inserted section 82 is equipped at a free end thereof withan illuminating portion 82 a for illuminating the inside of the mouthand a photodetecting portion 82 b. A plug which is connected to a freeend of the cord 86 is inserted in the external input terminal 67, andthe selector switch 69 is changed over toward the camera. The free endof the intraorally-inserted section 82 of the camera 80 is inserted intothe mouth of a patient, and a part photography of which is desired isilluminated by the illuminating portion 82 a. Reflection light from thepart is detected by the photodetecting portion 82 c, and the light sodetected is converted into video signals by a CCD sensor or the like.These video signals are then transmitted to the display system 60 viathe cord 86. At the display system 60, an image T of teeth is displayedon the LCD 66 on the basis of the video signals. Use of theabove-described system makes it possible to selectively display both ofa photofluorographic image on the basis of an x-ray film and a visualimage obtained by the camera 80. This makes it possible to moreprecisely determine the condition of teeth and hence to perform moreappropriate diagnosis and treatment.

Recently, a new x-ray photographing method is performed. According tothis new method, an x-ray CCD sensor is inserted in the mouth and ispositioned in contact with the inner sides of teeth the x-rayphotography of which is desired. X-rays are irradiated from the outsidesuch that an image of the object is formed on a surface of the CCDsensor. It is therefore possible to display an image by inputtingsignals from an x-ray CCD sensor 87 into a video signal generator 88 toproduce video signals and then inputting the video signals to the filmimage display system 60, as illustrated in FIG. 6B. Here, the imagesignal generator 88 is provided with memory means for storing videosignals. The above-described system requires only the x-ray CCD sensor87, the video signal generator 88 and LCD 66 and makes it possible toobtain an x-ray dental image by the simple construction. Moreover,observation of the image with an explanatory sketch or the like directlydrawn on the sheet 32 and/or with the scale marks 32 a maintained incontact with the image makes it possible to achieve a precise diagnosisand to obtain an informed consent even if the system is not equippedwith a costly digital computer.

The sheet 32 in FIGS. 6A and 6B is of the rolled type. As analternative, a cut paper sheet 90 depicted in FIG. 9 may also be used.The sheet 90 is transparent or translucent, and no particular limitationis imposed on its material. It may be made of paper, a resin or the likeinsofar as writing is feasible with a writing instrument. An adhesive 92is coated along edges of the sheet 90. With this adhesive, the sheet 90can be bonded to a surface of LCD 66. After the sheet becomes no longerneeded subsequent to the drawing of an explanatory sketch on the sheet,the sheet can be readily peeled off and replaced by a fresh sheet. Thesheet 90 may be applied with cross-ruled scale marks 94.

Referring next to FIG. 7, the transparent case mount 68 will bedescribed in detail. The transparent case 26 is inserted in acase-mounting slot 68 a formed in the mount 68. A plurality of lightsources 70 and an optical system 72 are arranged opposite sides of theslot 68 a, respectively, such that the slot 68 a is interposed betweenthe light sources 70 and the optical system 72. Light from the lightsources 70 advances through the film 20, and is converged by the opticalsystem 72 so that an image is formed on a CCD sensor 74. Image data ofthe film 20 are outputted from the CCD sensor 74 to an image processor(not shown) in the main body 64, whereby a film image T such as thatillustrated in FIG. 6B is displayed. In place of the above-describedoptical system 72 and CCD sensor 74, a CCD camera or the like may alsobe used.

Use of the above system makes it possible not only to bring aboutsimilar advantageous effects as the system of FIG. 1 but also to makethe whole system compact owing to the use of LCD. The above system istherefore convenient for a dentist to keep it at hand for use in makingexplanations to patients.

FIG. 8 illustrates, by way of example, the transparent case which isdesignated at numeral 26 and carries scale marks 26 a applied thereon.The scale marks 26 a may be applied by directly printing them on thetransparent case 26 or by affixing a seal, on which the scale marks areprinted, onto the transparent case 26. As a consequence, the scale marks26 a are displayed on the photographed image. Advance setting of thescale of the scale marks therefore makes it possible to preciselydetermine the dimensions of a photographed part, thereby facilitatingthe observation and measurement of teeth (measurement of their rootcanal lengths). The accuracy of a measurement becomes better as thescale marks 26 a are arranged with smaller intervals. The accuracy canbe selected as desired depending on the purpose of use or the like.Because the pattern of the scale marks has already been applied to theoriginal image and the original dimension of the scale marks is known,the dimensions and the like of teeth can be easily determined even whenthe resulting digital image is subjected to various image processing. Inother words, measurements of teeth can be easily performed withoutneeding complex software processing such as those required byconventional dental digital x-ray systems.

The scale marks may be formed on a surface of LCD 6.

The transparent case 26 also has valuable utility by itself. Describedspecifically, accommodation of a developed film together with a clearliquid in the transparent case makes it possible to read the image ofthe film even if the film is wet. Further, formation of scale marks on asurface of the transparent case 26 can bring about the above-mentionedadvantageous effects. This transparent case 26 may be combined withimage pickup means such as a camera. This combination makes it possibleto easily obtain video signals indicative of the image of the film, andthe image of the film can be easily displayed by inputting the videosignals to a conventional monitor or the like.

The above-described systems 2, 60 may be provided with a mode in whichthey can be used as film viewers for checking films. For example, thesesystems can be used as film viewers by providing them with a mode inwhich the view screen is rendered brighter in the screen 12 or a displaysuch as LCD or CRT.

In the embodiments described above, water was used as a liquid. However,the liquid is not limited to water, and colored liquid may also be used.In essence, liquids other than water may be used insofar as they areclear. Further, the sheet 32 was described by taking a continuous papersheet such as a rolled paper sheet as an example. The sheet is howevernot limited to such a continuous paper sheet, and a cut paper sheet maybe applied onto the view screen. In the embodiment shown in FIG. 1, theimage was directly projected onto the screen 12 from the projection lens22. A more enlarged image can however be obtained while keeping thesystem compact, provided that the film is projected onto the screen 22by deflecting light with one or more deflection mirrors or the like. Assuch deflection mirrors, those applied with a reflection-increasingcoating to avoid a reduction in the quantity of reflected light can beused preferably.

In general, the present invention can be applied to all developed films.Especially, use of the present invention for a dental film makes itpossible to promptly project an x-ray film on an enlarged scale afterits rinsing. The present invention can therefore bring about theadvantageous effect that a dental treatment and its explanation to apatient can be performed promptly in a manner readily understandable bythe patient.

This application claims the priority of Japanese Patent Application No.HEI 10-322770 filed Oct. 9, 1998, which is incorporated herein byreference.

What is claimed is:
 1. A film image display system for displaying animage of a developed film comprising a transparent case to hold a clearliquid, a film holder to hold a developed film in the clear liquid, asource of illumination disposed on one side of said transparent case,said transparent case being adapted to have a rear projection screendisposed on the other side thereof and spaced therefrom, and a lenssystem disposed between said transparent case and said rear projectionscreen at a predetermined distance to focus an image from said developedfilm onto said screen.
 2. A film image display system according to claim1, further comprising a writable transparent or translucent sheetarranged over a front side of said rear projection screen.
 3. A filmimage display system according to claim 2, wherein scale marks areformed on said transparent or translucent sheet.
 4. A film image displaysystem according to claim 1, wherein scale marks are formed on a surfaceof said transparent case.
 5. A film image display system according toclaim 1, wherein scale marks are formed on a surface of said screen. 6.A film image display system comprising a transparent case foraccommodating therein a developed film together with a clear liquid; asource of illumination disposed on one side of said transparent case; animage pickup device disposed on the other side of said transparent caseadapted to read an image of said film which is accommodated in saidclear liquid within said transparent case and illuminated by said sourceof illumination, said image pickup device generating video signals.
 7. Afilm image display system according to claim 6, wherein a writabletransparent or translucent sheet is arranged over a front side of saiddisplay.
 8. A film image display system according to claim 6, whereinscale marks are formed on said transparent or translucent sheet.
 9. Afilm image display system according to claim 6, wherein scale marks areformed on a surface of said transparent case.
 10. A film image displaysystem for displaying an image of a developed film comprising atransparent case to hold a clear liquid, a film holder to hold adeveloped film in the clear liquid, a source of illumination disposed onone side of said transparent case, an optical system disposed on theother side of the transparent case at a predetermined distance to focusan image from said developed film onto a pickup device which generates asignal corresponding to said image.
 11. A film image display systemaccording to claim 10, further comprising an external input terminal forpermitting connection of an intraoral camera to said film image displaysystem.
 12. A film image display system according to claim 10, whereinsaid pickup device is a CCD.
 13. A film image display system accordingto claim 10, wherein said source of illumination comprises a pluralityof light sources.